(a) Field of the Invention
The present invention relates to a hybrid vehicle. More particularly, the present invention relates to a method and a system for protecting a battery of a hybrid vehicle in order to prevent overcharge of high voltage battery during running of the hybrid vehicle.
(b) Description of the Related Art
Because of demands for enhancement of fuel efficiency and reinforcement of exhaust gas regulations, eco-friendly vehicles have been a focus of many research projects in the automotive industry. A hybrid vehicle is one type of such eco-friendly vehicles and has recently attracted a large amount of public attention.
A typical hybrid vehicle includes an engine, a transmission, a motor, an inverter system, and a high voltage battery. This engine, transmission, motor, inverter system, and high voltage battery are controlled by a controller so as to generate target power. Since the motor is driven by electricity from the high voltage battery in the hybrid vehicle, an interior permanent magnet motor which has characteristics of wide speed control region and wide torque control region is used so as to obtain high efficiency characteristics. If the interior permanent magnet motor fails while operating at a high rate of speed, high voltage occurs due to the permanent magnet rotating at a high speed.
In addition, the high voltage generated by malfunction of the motor is supplied to the high voltage battery due to the batter being an energy storing device of the hybrid vehicle through the inverter system as an excess charging voltage. Therefore, life of the high voltage battery may be shortened and/or the high voltage battery may be damaged in more serious cases should this occur. Even further, if the high voltage batter is not adequately protected from this voltage surge, the security of the driver cannot be effectively guaranteed, i.e., a fire could occur.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.